Under Pressure

Imagine you are waiting on the platform for a trolley. When it comes into view the driver is waving his arms in a panic as sparks fly from the rails. Glancing down the tracks, you see three rail workers whose demise is inevitable unless you halt the trolley … by pushing the person next to you onto the tracks. Not a decision anyone wants to make, but that’s the point, says Jill Portnoy, a graduate student in criminology who is studying biological responses and their relation to psychopathic and antisocial tendencies.

Thankfully, no bystanders or study participants were hurt. The ordeal did succeed in getting useful biometric readings, however. In order to chart responses participants were outfitted with electrodes to monitor heart rate and skin conductance, which is affected by how much you sweat and is used as an indicator of your state of arousal.

“The dilemmas present purposefully unattractive options in order to measure the body’s response to potentially life-altering decisions that may involve the safety of others—or even one’s own child,” says Portnoy. “The hypothesis is that those on the psychopathic spectrum will have a limited emotional—and therefore biological—response.”

The study represents the culmination of multiple projects Portnoy is completing for her dissertation. It builds upon previous research conducted in Richard Perry University Professor Adriane Raine’s lab. Raine, a renowned neurocriminologist, has conducted numerous studies on the interaction between social and biological factors in predisposing one to crime.

“In Professor Raine’s lab we are able to collect and process data right here at Penn, instead of depending on collection from outside sources,” says Portnoy. “It has been an invaluable learning experience for me.”

Portnoy also examined what is called the 2D:4D ratio, or the ratio between the index and ring finger. Often thought to be a marker for pre-natal testosterone levels, it can hypothetically be used to chart aggression.

“People who are more aggressive tend to have lower heart rates,” Portnoy says. “We think this leads to arousal-seeking behavior, because for them, the low heart rate presents as an uncomfortable state.”

In addition, she is collaborating with Raine to analyze heart rate changes in children from high-risk environments. The results share similarities with her other research.

“What we’ve found is that kids who are less reactive to stressful situations and who have lower heart rates during stressful laboratory tasks seem to be more vulnerable to their negative surroundings.”

So what is the “normal” answer to the trolley dilemma? “We think that those participants who exhibit typical responses will not be willing to sacrifice a life, even if to save others, while those who exhibit antisocial tendencies will base their decision more upon cold logic," says Portnoy.